Document Type
Thesis - Open Access
Award Date
2025
Degree Name
Master of Science (MS)
Department / School
Mechanical Engineering
First Advisor
Solaiman Tarafder
Abstract
This study presents the development of a collagen-based bioink for 3D printing tendon-to-bone tissue grafts, specifically designed for rotator cuff repair applications. Three different bioink formulations were developed: (i) 5.1% (w/v) collagen I, (ii) 5% (w/v) collagen I and collagen II, and (iii) 4.5% (w/v) collagen I combined with β-TCP. The bioink containing collagen I and collagen II was prepared by mixing the two components in a 1:1 ratio, while the collagen I plus β-TCP formulation was made by incorporating 20 wt % β-TCP into the collagen I solution. These formulations were developed to replicate the natural tendon-to-bone complex interface closely. The bioink demonstrated favorable rheological properties for bioprinting, including shear-thinning behavior, a high storage modulus (G') relative to the loss modulus (G"), and excellent long-term stability. These characteristics ensured that the scaffold maintained its shape and structural integrity during the 3D printing process and in the post-printing period. Consistent viscoelastic performance was validated across varying strains and temperatures, confirming the bioink's reliability for scaffold fabrication. The 3D-printed scaffold exhibited a biomimetic architecture, verified by SEM imaging, with interconnected macropores and micropores that are critical for cellular attachment, proliferation, and nutrient exchange. These scaffolds featured a porosity between 70–80%, which is beneficial for cell migration, cell viability and efficient nutrient distribution. Mechanical properties were significantly enhanced through EDC/NHS crosslinking, achieving a stiffness of 2500 ± 100 kPa and a tensile strength of 450 ± 25 kPa, making it suitable for rotator cuff repair application. A unique layered design introduced a gradual transition to support a native-like tendon-to-bone interface formation. This combination of biomimetic structure with high porosity and robust mechanical properties positions our multi-layered biomimetic collagen tissue graft as a promising solution for rotator cuff repair applications.
Publisher
South Dakota State University
Recommended Citation
Nibir, Samiul, "Development of a Collagen-Based Bioink for 3d Printing Biomimetic Tendon-To-Bone Tissue Grafts for Rotator Cuff Repair" (2025). Electronic Theses and Dissertations. 1549.
https://openprairie.sdstate.edu/etd2/1549
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